Traffic control system



Oct. 8, 1935. c, GEER 2,016,325

TRAFFIC CONTROL SYSTEM Filed NOV. 1, 1930 [If/0 l0 12 Fig .2 6

/e q 2a Jifl-C'.

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INVENTOR.

CHARLES D. 65.52,

"M, emu M ATTORNEYS.

Patented Oct. 8, 1935 UNITED STATES PATENT OFFICE TRAFFIC CONTROL SYSTEMnecticnt Application November 1, 1930, Serial No. 492,731 7 Claims. (Cl.I'M- 337) This invention relates to a functionally and structurallyimproved trafllc control system and apparatus forming such system.

It is an object of the invention to provide a system and apparatus ofthe nature stated capable of use in numerous different associations butprimarily intended to be employed at the point of intersection of twovehicle lanes and specifically vehicle lanes of the automobile type.Where so employed, the present apparatus will provide a systemfunctioning in response to the flow and condition of traflic and whichsystem will operate in an improved manner to prevent accidents at thepoint of intersection and will additionally expedite to a maximum extentthe traffic flow.

A further object of the invention is that of furnishing an apparatus forcontrolling the flow of traffic in such manner that a vehicle orvehicles traversing one lane will have ample opportunity to negotiatethe intersection before right of way is transferred to the other vehiclelane.

Another object is that of furnishing an apparatus of this character, theparts of which will be relatively few in number and individually simpleand rugged in construction, these parts functioning over long periods oftime with freedom from mechanical and electrical difliculties.

With these and other objects in mind, reference is had to the attachedsheet of drawings illustrating one practical embodiment of theinvention, and in which:

Fig. 1 shows diagramatically the intersection of two vehicle lanes andmoreover illustrates an apparatus embodying the present invention and inassociation with such lanes; and

Fig. 2 is a similar view of a detailed layout of apparatus suitable toachieve the results to be accomplished by the present invention.

For the sake of simplicity of illustration, the present invention hasbeen shown as embodied in a, traflic control system installed at thepoint of intersection of a cross street and main highway. In thedrawing, the latter is indicated at A and the cross street is designatedB. As hereinafter described and in line with this example, vehicleactuated controls are shown only in the cross street. However, underactual installation conditions, these controls will usually although notnecessarily be in both Streets or in any further number of streets whichmay exist at the point of intersection.

Thus as illustrated, a signal 5 is disposed conveniently adjacent thepoint of intersection of the two lanes and has signal lights visible tovehicles moving along such lanes and approaching the intersection. Theselights have been indicated at 6 to 9 inclusive in Fig. 2 and embracepreferably two green lights and two red lights, the former indicatingright of way and the latter signalling a halt to the vehicles. To thisend, these lights are preferably colored green and red respectivelywhich coloration may be achieved by the use of colored'bulbs and/orlenses or in any other suitable manner. Moreover; if the presentinvention is embraced in a system of the nature afore referred to, thevehicle actuated or responsive controls Ill or II are disposed in onlythe cross street. While the signalling means a may be of any desiredcharacter and the vehicle actuated controls may also embrace anymechanism suitable to operate in response to the passage of a vehiclealong the vehicle lane, it is preferred that such controls be in thenature of pressure operated switches which incident to the passage ofv avehicle function in order to close a circuit. It will be observed that aplurality of these switches are, in the present exemplification,associated with the cross street. These switches are connected inparallel and arranged two to each side of the intersection. Accordingly,actuation of one of these controls will close the circuit common to allof them. For the sake of simplicity only two controls have been shown inFig. 2 and indicated by the reference numeral l l.

The functionings of the signalling means 5 in response to actuations ofthe controls l0 and H are governed by a timer or control mechanism l2,the detailed construction of which has been shown in Fig. 2. In thisview and as afore brought out, the several vehicle actuated controls IDare shown in the form of parallel switches l I. A closing of eitherswitch permits current to flow from lead I3 through quick acting relay[4 and thus to lead IS. The leads l3 and I5 are connected to a source ofpower supply (not shown) and the armature of the relay It serves to movea switch l6 from engagement with the contact arranged at the end of leadI! into engagement with the contact at the end of lead I8.

The parts as shown in Fig. 2 die in a normal position, but anenergization of the relay will as afore stated move the switch ll whichwill permit current to flow from lead I! through lead It, thence throughrelay l8 and so through lead 22 to lead It. This will serve to operateand lock in relay ll by virtue of the fact that the armatures controlledthereby will shift the switches 2| and 22 into engagement with contactsforming parts of leads 22 and 24 respectively. Thus even though theswitch it move rapidly out of engagement with the contact of lead ll,current will now flow through lead 25, a switch 28 interposed therein,lead 22, switch 2|, relay I! and so through lead 20 to lead I5. As aforebrought out, the switch 22 moves into engagement with a contactassociated with the lead 24 and current willnow flow through this leadand relay 21, lead 20 and switch 2! from lead ll. Consequently, switches40 and II will move to closed positions, thus through the formerpermitting current to flow through lead 32 and relay 23 interposedtherein, through this switch, lead 24, switch 22 and so to lead It. Withthe closing of switch 21, current may flow through lead 34, switch 35interposed therein, and thence through switch II and so to lead II.

Relays i 4, i9, 21 and 88 are of the substantially instantaneous types.The switches 26, 2| and 29 are controlled by time delayed relays 38, 21and 38 which may conveniently be of the oil dash pot type. In theembodiment under consideration, the first of these latter relays is setto open after five seconds, the second relay is set to open after thirtyseconds and the third relay is set to close thirty seconds after havingbeen continuously energized. All three relays return to theirdeenergized position substantially instantly. However, this time factormay be varied largely according to the conditions of installation whichare met with. Finally, it will be observed that the lead I! may alsosupply current through the lead 29 to the signalling means or lights Iand 9 interposed therein, and thence through switch 40 to the lead It.This switch is controlled by relay 23 as is also a switch 4| interposedin a lead 42 within which there is additionally interposed the relay ll.Finally, it will be observed that the relay 23 shifts the switch 40 to apoint at which it engages the contact associated with lead 43 withinwhich are interposed thesignalling means or lights 8 and 1 which latterwhen energized served to signal Stop to.the highway and to accord rightof way to the cross street.

With a set up of the parts such as that herewith illustrated, it will beobvious as afore brought out that an energization of the relay l4follows each closing of the switch ll. Also as afore brought out, thisresults in a locking in of the relay I! in turn energizing relay 21 topermit current to flow through lead 32 and relay 13 from lead It to leadI 5. Consequently, an immediate shifting of the'switches 40 and 4|follows and right of .way is transferred from the highway to the crossstreet by virtue of the extinguishing of lights I and 8 and theenergizing of lights 6 and 1.v The energizing of the relay 33 will alsocause circuit through relay 38 to be broken and the switch 29 willconsequently move out of engagement with the contact at the end of thelead 28.

All of this will occur under usual conditions of operation upon avehicle approaching over cross street B and operating the first vehicleactuated control. of the pair. Under the setting of the parts and withrelays i9 and 21 energized, relay 28 will be potentialized to operate infive seconds. However, due to the fact that the vehicle still has tonegotiate and operate the second control, it will be obvious that thisrelay will be reset substantially instantly before the vehicle reachesthe point of intersection. In other words, due to the closing of thesecond switch II, the relay l4 will again be energized to shift theswitch I and thus break the circuit through relay 3', the latteraccordingly being reset to require the full time interval before itoperates. Upon the expiration of such time interval, the switch 24 isopen and current will accordingly no longer flow through lead 23 thuscausing a deenergization of relay' l9 and permitting the switches 2| and22 of the latter to open. Consequently, relay 21 will also bedeenergized and as a result, relay 2! will be deenergized so thatswitches 40 and 4| will move back to the positions illustrated in whichfirst current is being supplied to relay 38 and secondly the right ofway is transferred from the cross street in favor of the highway due tothe extinguishing of signals 6 and 1 and the reinstatement of signals 8and 9.

If thereupon a further vehicle approaches over lane B and operates thevehicle actuated controls resulting in a closing of the switch Ii, relayi4 will function to again operate switch I! and thus lock in relay IS inthe manner afore described. However, due to the fact that relay 2|requires-in the example given-thirty seconds to shift its armature sothat the circuit through wire 2! is closed the switch 29 will be openand consequently the relay 21 can not be energized. Accordingly, nochange in condition results despite the presence of a vehicle and thelatter must wait a full thirty second period before transfer of right ofway occurs. At the end of this period, relay ll shifts switch 29 toclosed position and thereupon the relay 21 functions to operate relay 3!so as to transfer right of way in the manner afore described and thecycle of. operations is again repeated.

However, it will be recalled that the vehicle has come to a standstillafter operating the first vehicle actuated control. Ordinarily thevehicle could gather sufficient momentum to negotiate the intersectionfive seconds after the transfer of right of way, but, while this vehiclewould be able to get clear of. the intersection before the right of waywas retransferred, it will be obvious that in the case of a second,third and possibly more vehicles having passed the distant vehicleactuated control and awaiting suchright of way, the delay factor ofgetting these vehicles under way after transfer of right of way would besuch that they could not conceivably negotiate the intersection withinthe time interval allowed without the provision of the second vehicleactuatcd control. Accordingly, immediately in advance of theintersection, the second vehicle actuated control is arranged andtherefore the second, third and other vehicles awaiting right of waywill operate such control, causing a five second delay interval in theretransfer of right of way. Thus, all the vehicles will have ample timeto negotiate the intersection, it being understood that each time therelay I 4 operates, the relay 38 will be reset.

It would appear that the second vehicle actuated control might performall necessary functions and that the distant control might be dispensedwith. Such is not the case. A vehicle should register its presencesufficiently in advance of arriving at the intersection so that if itreceives right of way immediatelyitcan avail itself thereof beforedeceleration is necessary; On the other hand, if the vehicle will haveto await right of way, it should have registered its pres-'- ence beforedeceleration begins, so'that ample space is available for stopping. I iv Occasionally, a very heavy flow of traffic may occur on the crossstreet and this-might prevent the highway from receiving right of wayfora long period of time. However, due to the provision of relay 31, itwill be obvious that right of way may not be retained in favorof thecross street for an indefinite period. 'As illustrated and described,this relay will function after thirty seconds to open the switch 35.This will cause the circuit through relay 21 to be interrupted, thusreturning the signal to normal condition and closing the circuitthroughrelay 38. Consequently, the parts will return to their normal conditionexcept that relay l9 will remain locked in and, as a result, right ofway whichhas been transferred in favor of the highway will beretransferred back to the cross street'afte'r thirty seconds.

It will be understood that, the innermost vehicle actuated controls, 1,e. those controls which are nearest to the intersection, might bedisposed at points relatively remote therefrom. For example, thesecontrols might be anywhere from 25 to I feet from the intersection whilethe outermost controls might be as much as 200 to 300 feet away. Thiswill be particularly true where the present invention is incorporated ina layout of apparatus to be installed at cross streets where hightrafllc speeds may occasionally be encountered. It will be obvious thatin addition to the vehicle actuated controls illustrated-and as aforebrought out--that the vehicle actuated controls will exist in the secondlane. Where the innermost controls are substantially immediatelyadjacent the intersection, the advantages of the reset period and themanner in which the ap- ,iaratus will function in the case of a numberof vehicles awaiting right of way will be obvious. Where the innermostcontrols are somewhat spaced from the point of intersection, it will beapparent that at best only a few vehicles awaiting right of way willmove beyond the innermost controls and these vehicles will haveopportunity to negotiate the intersection during the minimum periodgranted when right of way is given. If further vehicles are awaiting theright of way beyond the innermost controls they accordingly intraversing such controls will reset the apparatus to extend the minimumperiod.

Summarized, it will be apparent that with the parts in the positionillustrated in Fig. 2, a vehicle approaching over the cross street willcause-incident to an operation of the first vehicle actuated control-asubstantially immediate transfer of right of way in favor of the cross"street. If further vehicles are following the first named vehicle orare approaching over the cross street in the opposite direction andwithin a sumciently close time interval, these other vehiclesincident tooperation of the controlswill prolong the right of way for a period oftime adequate to permit their crossing the intersection. In this manner,the cross street right of way may be maintained according to the presentsetting of the parts up to a period of thirty seconds. At this time,regardless of whether further vehicles on the cross street wish theright of way, the right of way will be transferred to the highway.However, if such right of way is desired at that time the system williirememberittha-ipresence of such vehicles incidenttoithe lockingcin 'ofthe relay It or a functionally equivalent structureiso that at the endof thewhighwaysarightr of siway period, a retransfer of rightof-zway itbtheicrbss e street will occur. The sa'meresult willlbe trueiin the caseof vehicles arriving during the liighway right of way period. 1 Byvirtue of providing a multiplicityz'of .velii actuated controls, thefollowing salient advantages among others are derived: firstg inthe-case of a vehicle moving over the' 'cross street'toward theintersection, the right of waiy giv' wane crossstreet will be retalnedfor a period ropontional to the speed of the'vehiclei Iri' othe .words,1 5 the spacing of the vehicle somerset-sham their distance from thepoint of intrseotiom etc be so proportioned'that one may safely sayhatno vehicle will require less thanslightlyinexcess of five secondstonegotiate the intersection amt having operated the first vehicleactuate trol. Consequently, such vehicle will oprat first control andwhileit continues' 't'o mo i the cross street, right of way will be"transferred 7 r for a five second period incident to'flthe setting ofthe relay 36. This relay however'will b reset by the same vehicleincident to'operation the second control and this resetting will be forire period. Now, assuming as More brought out, M, that the vehicle ismovingathighspeed, w'' 'inii'y arbitrarily say, for the sake of example,thatbril'y one second will be required for it to negotiate tlie'distance between the first and second 'coiiti'ol.

The second control resets the right'of'way period for an additional fiveseconds. Consequentlyflthie entire right of way period in favor of-thecrj'os's street will be six seconds. "In the'caseofaslow moving vehicle,four seconds maybe required tween operation of the first controland the'se ond control, making a total of nine second Second, in the case of avehicle arrivih' at the time that right of way is transferred aclr tothe highway, or during the right ofway pe- .riod of the highway, notrahsrer' r rig ts: way

to the cross street will result despite the operation of the vehicleactuated control. However, afore brought out, the system willremember'thisf. After the expiration of the highway righ 'of way period,the system will accordingly-transfer right of way back to the crossstreet. It will "here"- membcred that the vehicle is at a standstill,and would have five seconds to negotiate thefintersection. This would besufficient for one or passibly two vehicles, but if furthervehicls'arrived during the highway right of way period andwere awaitingright of way, five seconds would not be suificient time for them tonegotiate the intersection. However, by virtue of providing the secondcontrol, five seconds-in the example givenis allowed from the time thiscontrol is operated until right of way retransfers. Accordingly,.arn'-ple opportunity will exist for all additional waiting vehicles tooperate this second control and to negotiate the intersection up to themaximum right of way period for which the relay 3] orits equivalentstructure is set. I I Under varying conditions, the spacingof-thevehicle actuated controls would be changed in many respects and theproximity of these controls to the point of intersection would also bealtered. Obviously, in lieu of the dash pot relays referred to, anyother suitable mechanism might be employed and as afore brought out, thesystem might be altered according to the particular needs of theinstallation without departing from the spirit of the invention asdefined by the claims.

Having described my invention, what I claim as new and desire to secureby Letters Patent, is:

l. A traiiic control system including signalling means to be disposedadjacent the intersection of two vehicle lanes and to accord andinterrupt right of way to vehicles moving over said lanes, control meansconnected to said signalling means to cause such operation thereof and apair of spaced vehicle-responsive controls disposed in one lane to oneside and in advance of said intersectlon, said vehicle-responsivecontrols being connected to said control means and adapted to besequentially operated by a vehicle approaching the intersection oversuch lane and means forming a part of said control means wherebyoperation of the first vehicle-responsive control causes transfer ofright of way indication to the lane in which said controls are disposedand maintains said right of way indication for a period of time. andactuation of the second vehicle responsive control causing said controlmeans to lengthen such period of right of way indication.

2. A tramc control system including, in combination, signalling means tobe disposed at the intersection of a plurality of tramc lanes and toalternately accord and interrupt right of way to tramc moving over saidlanes and through said intersection, timing means controlling theoperation of said signalling means, a mum: responsive caitrol disposedin one of said lanes and connected to said timing means to accord whenactuated through said signalling means right of way to said lane for aminimum period, said traiiic responsive control being located at a pointrelatively remote from the intersection and a further traiiic responsivecontrol connected to said timer to extend when actuated the right of wayperiod of such lane, said further control being disposed at a pointrelatively close to the intersection.

8. A traiilc control system including, in combination, signalling meansto be disposed at the intersection of a plurality of traiiic lanes andto alternately accord and interrupt right of way to tramc moving oversaid lanes and through said intersection, timing means controlling theoperation of said signalling means, a trai'iic responsive controldisposed in one of said lanes and connected to said timing means toaccord when actuated through said signalling means right of way to saidlane for a minimum period, said traffic responsive control being locatedat a point relatively remote from the intersection and a further tramsresponsive control connected to said timer to extend when actuated theright of way period of such lane, said further control being disposed ata point relatively close to the intersection, and means forming a partof said timing means for terminating the right of way period of saidlane.

4. A traiiic control system including, in combination, signalling meansto be disposed at the intersection of a plurality of trainc lanes and toalternately accord and interrupt right of way to traiiic moving oversaid lanes and through said intersection, timing means controlling theoperation of said signalling means, a traiiic actuated control disposedin one of said lanes at a point relatively remote from the intersectionand connected to said timing means to accord when actuated through saidsignalling means right of way to said lane for a minimum period, meansforming a part of id timing means to automatically transfer through saidsignalling means the right of way from said lane to another lane uponthe expiration of said minimum period, and a further traffic actuatedcontrol connected to said timer to prevent, upon actuation, theautomatic transs fer at the end of the said period, and to extend theright of way period of such first named lane beyond the said minimumperiod, said further control being disposed at a point relatively closeto the intersection. l

5. A traiiic control system including, in combination, signalling meansto be disposed at the intersection of a plurality of tramc lanes and toalternately accord and interrupt right of way to traffic moving oversaid lanes and through said intersection, timing means controlling theoperation of said signalling means, a traflic responsive controldisposed in one of said lanes and connected to said timing means toaccord when actuated through said signalling means right of way to saidlane for a minimum period, means forming a part of said timing means toautomatically transfer through said signalling means the right of wayfrom said lane to another lane upon the expiration of said minimumperiod, further means forming a part of said timing means to maintainthe transferred right of way in favor of said second lane for adetermined period, the traflic responsive control of said first namedlane being located at a point relatively remote from the intersectionand a further traflic responsive control connected to said timer toprevent, upon actuation, the automatic transfer of right-of-way at theend of such minimum period, and to extend the period of such first namedlane, said 36 further control being disposed at a point relatively closeto the intersection.

6. A traiiic control system including, in combination, signalling meansto be disposed at the intersection of a plurality of traiiic lanes andto 40 alternately accord and interrupt right-of-way to traffic movingover said lanes and through said intersection, timing means controllingthe operation of said signalling means, a traiiic actuated controldisposed in one of said lanes at a point relatively remote from theintersection and connected to said timing means to accord, whenactuated, through the signalling means, right of way to said lane for aminimum period, means forming a part of said timing means to automat- 60ically transfer through said signalling means the right-of-way from saidlane to another lane upon the expiration of said minimum period, and afurther traiiic actuated control connected to said timer to prevent,upon actuation, the automatic transfer at the end of the said period,and to extend the right-of-way period of such first named lane beyondthe said minimum period, said further control being disposed at a pointrelatively close to the intersection, and means forming a part of saidtimer to prevent continued extension of right-of-way to such first namedlane beyond a predetermined period.

7. A trafiic control system including, in combination, signalling meansto be disposed at the intersection of a plurality of traiiic lanes andto alternately accord and interrupt right-of-way to said lanes, timingmeans controlling the operation of said signalling means, a plurality ofyehicle responsive controls disposed in one lane to 7 one side and inadvance of said intersection, one of said controls being locatedrelatively remote from the intersection and connected to said timingmeans so that when actuated while right-ofway is not accorded to thelane of said control tion, the right-of-way period for at least aninterval sufiicient to permit passage of a vehicle to a control nearerthe intersection and the control nearest the intersection, uponactuation extends through said timing means the right-of-way pe riod fora further interval sufiicient to allow passage of the vehicle across theintersection.

CHARLES D. GEER.

